1. Field of the Invention
The present invention relates to a printing system including a server and a plurality of clients connected by a network system.
2. Description of the Related Art
There has been known a printing system with one or more client devices connected to a shared printer by a network. The printing system has a spooling function, wherein the client devices transmit print data and print management information data for print jobs to the printer, and the printer stores the print data and associated print management information data in job units in a hard disk.
The print management information data includes data representing time and date that the print data can be deleted, data representing the name of the person who transmitted the print data, data representing the time and date that the print data was transmitted, and data representing the time that the print data was printed out. Based on this print management information data, the printer prints starting with print data that was transmitted first, that is, with the oldest transmission time and date. Also, the printer can delete print data from the hard disk when the deletion time and date arrives or the printer can notify the user that the printing operations have been completed when they are completed.
Sometimes a user of one of client devices wishes to know the condition of print processes that the user of another client device is attempting to execute. The print management information describes the condition of printing processes for each print job. Therefore, the user merely needs to access the printer through the client device in order to confirm the condition of printing processes by referring to the print management information.
However, the condition of printing processes may change directly after the user accesses the printer and confirms the condition of printing processes. That is, printing processes may be executed with respect to certain print data or the print data itself may be deleted. In such cases, any printing processes that the user attempts to execute may be influenced by such changes in the printing process status. Further, in order for the user to accurately grasp the present condition of printing processes, the user must frequently access the printer, which is very troublesome for the user.
In one known printing system, the shared printer maintains the sets of data stored in a hard disk after printing is completed. When the printer receives a reprint command from one of the user device, the printer again prints out based on the print data. This configuration is highly convenient for the user, because the user can print out the same text or images using the same print data, without having to resend the print data.
However, with this type of printing system, the data remains stored in the hard disk unless the user specifically erases it. However, it is troublesome to monitor the contents stored in the hard disk and delete unnecessary print data. Therefore, print data tends to remain in the hard disk of the printer for long periods of time.
Since the region in the hard disk for storing such print data is limited, the capacity of the region can easily be filled up when the user does not diligently delete such print data. If the capacity of the region is exceeded, the it becomes impossible to store any further new print data.
Also, if a number of client devices connected to the network increases, the number of printer data sets sent to the printer and stored in the hard disk of the printer will increase by a proportional amount.
Also, once the computer transmits the print management information data with the print data, there is no way to amend the data even if it includes errors. Accordingly, if print management information data indicates an incorrect deletion time and date, then the printer will erroneously delete the print data at a timing different from when it should be deleted. As a result, the user must retransmits the same print data.
Such printer systems often include a mail server with an electronic mail function. The mail server transmits and receives e-mail messages between the various client devices.